Question

SystemVerilog adds several design and verification constructs including:

• C data types such as int, struct, union, and enum.
• Advanced built-in data types such as string.
• User defined data types and corresponding methods.
• Data types and facilities that enhance the creation and functionality of testbenches.

The access API shall be implemented by all tools as a minimal set for a standard means for user-tool or tooltool interaction that involves SystemVerilog object data querying (reading). In other words, there is no need for a simulator to be running for this API to be in effect; it is a set of API routines that can be used for any interaction for example between a user and a waveform tool to read the data stored in its database. This usage flow is shown in the figure below.

Figure 30-2 — Data read VPI usage model

The focus in the API is the user view of access. While the API does provide varied facilities to give the user the ability to effectively architect his or her application, it does not address the tool level efficiency concerns such as time-based incremental load of the data, and/or predicting or learning the user access. It is left up to implementers to make this as easy and seamless as possible on the user. To make this easy on tools, the API provides an initialization routine where the user specifies access type and design scope. The user should be primarily concerned with the API specified here, and efficiency issues are dealt with behind the scenes.